Debugger: Difference between revisions

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Debugger (view source)

Revision as of 02:43, 15 December 2011

882 bytes added ,  15 December 2011
Move watchpoint API to Debugger.Object; define full-object watchpoints; fix watchpoint handler method return values; add extensionsPrevented.
(→‎Accessor Properties of the Debugger.Frame Prototype Object: Specify that the frame is given as 'this' to onStep and onPop.)
(Move watchpoint API to Debugger.Object; define full-object watchpoints; fix watchpoint handler method return values; add extensionsPrevented.)
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<li>request notification of basic debugging events by assigning a handler object to <code><i>d</i>.hooks</code>;
<li>request notification of basic debugging events by assigning a handler object to <code><i>d</i>.hooks</code>;
<li>set breakpoints by obtaining a <code>Debugger.Script</code> instance and calling its <code>setBreakpoint</code> method;
<li>set breakpoints by obtaining a <code>Debugger.Script</code> instance and calling its <code>setBreakpoint</code> method;
<li>set watchpoints by calling <code><i>d</i>.setPropertyWatchpoint</code>;
<li>set watchpoints on objects and their properties;
<li>examine the debuggee's stack frames and lexical enviroments;
<li>examine the debuggee's stack frames and lexical enviroments;
<li>inspect and manipulate its objects;
<li>inspect and manipulate its objects;
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<dt>clearAllBreakpoints()
<dt>clearAllBreakpoints()
<dd>Remove all breakpoints set using this <code>Debugger</code> instance.
<dd>Remove all breakpoints set using this <code>Debugger</code> instance.
<dt>setPropertyWatchpoint(<i>object</i>, <i>name</i>, <i>handler</i>) <i>(future plan)</i>
<dd>Set a watchpoint on the own property named <i>name</i> of the referent of the <code>Debugger.Object</code> instance <i>object</i>, reporting events by calling <i>handler</i>'s methods. <i>Handler</i> may have the following methods, called under the given circumstances:
<dl>
<dt>add(<i>frame</i>, <i>descriptor</i>)
<dd>A property named <i>name</i> has been added to <i>object</i>'s referent. <i>Descriptor</i> is a property descriptor of the sort accepted by <code>Object.defineProperty</code>, giving the newly added property's attributes.
<dt>delete(<i>frame</i>)
<dd>A property named <i>name</i> has been deleted from <i>object</i>'s referent.
<dt>change(<i>frame</i>, <i>oldDescriptor</i>, <i>newDescriptor</i>)
<dd>The existing property named <i>name</i> on <i>object</i>'s referent has had its attributes changed from those given by <i>oldDescriptor</i> to those given by <i>newDescriptor</i>.
<dt>set(<i>frame</i>, <i>value</i>)
<dd>The property named <i>name</i> is about to have <i>value</i> assigned to it. The assignment has not yet taken place, so the debugger can use <i>getOwnPropertyDescriptor</i> to find the property's pre-assignment value (assuming it is not an accessor property). This call takes place whether the property is a data or accessor property, even if the property is not writable or lacks a setter. This call takes place even if the property is a value property and <i>value</i> is identical to its current value.
If the [[#Resumption_Values|resumption value]] this call returns has a <code>value</code> property, whose value is a debuggee value <i>newValue</i>, the assignment stores <i>newValue</i> instead of <i>value</i>.
<dt>get(<i>frame</i>)
<dd>The property named <i>name</i> is about to be read. This call takes place whether the property is a data or accessor property, even if the property lacks a getter.
</dl>
In all cases, the method's <i>frame</i> argument is the current stack frame, whose code is about to perform the operation on the object being reported. Methods should return [[#Resumption_Values|resumption values]]; however, watchpoint handler methods may not return <code>return</code> resumption values.
If a given method is absent from <i>handler</i>, then events of the given sort are ignored. The watchpoint retains a reference to the <i>handler</i> object itself, and consults its properties each time an event occurs, so adding methods to or removing methods from <i>handler</i> after setting the watchpoint enables or disables reporting of the corresponding events.
Values passed to <i>handler</i>'s methods are debuggee values. Descriptors passed to <i>handler</i>'s methods are ordinary objects in the debugger's compartment, except for <code>value</code>, <code>get</code>, and <code>set</code> properties in descriptors, which are debuggee values.
Watchpoint handler calls are cross-compartment, intra-thread calls: <i>handler</i> must be a function in the debugger's compartment (and thus calls to it take place in the debugger's compartment), and the call takes place in the same thread that changed the property.
The new watchpoint belongs to this <code>Debugger</code> instance; disabling the <code>Debugger</code> instance disables this watchpoint.
<dt>clearPropertyWatchpoint(<i>object</i>, <i>name</i>) <i>(future plan)</i>
<dd>Remove any watchpoint set on the own property named <i>name</i> of the referent of the <code>Debugger.Object</code> instance <i>object</i>.


<dt>clearAllWatchpoints() <i>(future plan)</i>
<dt>clearAllWatchpoints() <i>(future plan)</i>
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<dt>asEnvironment()
<dt>asEnvironment()
<dd>If the referent is a global object, return the <code>Debugger.Environment</code> instance representing the referent as a variable environment for evaluating code. If the referent is not a global object, throw a <code>TypeError</code>.
<dd>If the referent is a global object, return the <code>Debugger.Environment</code> instance representing the referent as a variable environment for evaluating code. If the referent is not a global object, throw a <code>TypeError</code>.
<dt>setObjectWatchpoint(<i>handler</i>) <i>(future plan)</i>
<dd>Set a watchpoint on all the referent's own properties, reporting events by calling <i>handler</i>'s methods. Any previous watchpoint handler on this <code>Debugger.Object</code> instance is replaced. If <i>handler</i> is null, the referent is no longer watched. <i>Handler</i> may have the following methods, called under the given circumstances:
<dl>
<dt>add(<i>frame</i>, <i>name</i>, <i>descriptor</i>)
<dd>A property named <i>name</i> has been added to the referent. <i>Descriptor</i> is a property descriptor of the sort accepted by <code>Debugger.Object.prototype.defineProperty</code>, giving the newly added property's attributes.
<dt>delete(<i>frame</i>, <i>name</i>)
<dd>The property named <i>name</i> is about to be deleted from the referent.
<dt>change(<i>frame</i>, <i>name</i>, <i>oldDescriptor</i>, <i>newDescriptor</i>)
<dd>The existing property named <i>name</i> on the referent is being changed from those given by <i>oldDescriptor</i> to those given by <i>newDescriptor</i>. This handler method is only called when attributes of the property other than its value are being changed; if only the value is changing, SpiderMonkey calls the handler's <code>set</code> method.
<dt>set(<i>frame</i>, <i>oldValue</i>, <i>newValue</i>)
<dd>The data property named <i>name</i> of the referent is about to have its value changed from <i>oldValue</i> to <i>newValue</i>.
SpiderMonkey only calls this method on assignments to data properties that will succeed; assignments to un-writable data properties fail without notifying the debugger.
<dt>extensionsPrevented(<i>frame</i>)
The referent has been made non-extensible, as if by a call to <code>Object.preventExtensions</code>.
</dl>
For all watchpoint handler methods:
<ul>
<li>The <i>frame</i> argument is the current stack frame, whose code is about to perform the operation on the object being reported.
<li>If the method returns <code>undefined</code>, then SpiderMonkey makes the announced change to the object, and continues execution normally. If the method returns an object:
<ul>
<li>If the object has a <code>superseded</code> property whose value is a true value, then SpiderMonkey does not make the announced change.
<li>If the object has a <code>resume</code> property, its value is taken as a [[#Resumption_Values|resumption value]], indicating how execution should proceed. (However, <code>return</code> resumption values are not supported.)
</ul>
<li>If a given method is absent from <i>handler</i>, then events of that sort are ignored. The watchpoint consults <i>handler</i>'s properties each time an event occurs, so adding methods to or removing methods from <i>handler</i> after setting the watchpoint enables or disables reporting of the corresponding events.
<li>Values passed to <i>handler</i>'s methods are debuggee values. Descriptors passed to <i>handler</i>'s methods are ordinary objects in the debugger's compartment, except for <code>value</code>, <code>get</code>, and <code>set</code> properties in descriptors, which are debuggee values; they are the sort of value expected by <code>Debugger.Object.prototype.defineProperty</code>.
<li>Watchpoint handler calls are cross-compartment, intra-thread calls: <i>handler</i> must be a function in the debugger's compartment (and thus calls to it take place in the debugger's compartment), and the call takes place in the same thread that changed the property.
</ul>
The new watchpoint belongs to the <code>Debugger</code> instance to which this <code>Debugger.Object</code> instance belongs; disabling the <code>Debugger</code> instance disables this watchpoint.
<dt>clearObjectWatchpoint() <i>(future plan)</i>
<dd>Remove any object watchpoint set on the referent.
<dt>setPropertyWatchpoint(<i>name</i>, <i>handler</i>) <i>(future plan)</i>
<dd>Set a watchpoint on the referent's property named <i>name</i>, reporting events by calling <i>handler</i>'s methods. Any previous watchpoint handler on this property for this <code>Debugger.Object</code> instance is replaced. If <i>handler</i> is null, the property is no longer watched. <i>Handler</i> is as described for <code>Debugger.Object.prototype.setObjectWatchpoint</code>, except that it does not receive <code>extensionsPrevented</code> events.
<dt>clearPropertyWatchpoint(<i>name</i>) <i>(future plan)</i>
<dd>Remove any watchpoint set on the referent's property named <i>name</i>.
</dl>
</dl>


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